Deep-drawing zinc alloy



Patented July 18, 1939 DEEP-DRAWING ZINC ALLOY Kurt Bayer, Magdeburg, and Arthur Burkhardt, Berlin-Lichterfelde, West, Germany, assig'nors to Georg von Giesches Erben, Breslau, Germany, a corporation 01' Germany No Drawing. .Application October 25, 1937, Se-

rial No. 170,854. In Germany December 4,

2 Claims.

Our invention relates to copper-zinc alloys, and more particularly to alloys for the production of deep-drawing sheets.

It is an object of our invention to provide an alloy of the kind referred 'towhich is more suit- Omission of aluminium would not result in any 5 able for deep drawing than the alloy known as' appreciable advantage with respect to ageing re- "63 brass, i. e., brass containing 63 per cent sistance while on the other-hand it would involve copper, employed almost exclusively for deep the drawback that the alloys could not bemelted drawing heretofore. in iron containers, as iron is strongly attacked by To this end, we provide an alloy containing 4 zinc alloys without aluminium. v 10 to 5.5 per cent copper, 0.1 to 0.2 per cent alu- By extensive investigations we have found that minium, and zincwhich is practically free from an alloy containing 4 to 5.5 per cent copper, not magnesium and cadmium as the remainder. more than 0.2 per cent aluminium, and zinc prac- Heretofore, there has been no lack of endeavtically free from magnesium and cadmium as the ours to replace the usual 63 brass by low-copper remainder, is absolutely resistant to ageing. 15 zinc alloys, and particular advantages were ex- The indicated content of aluminium so far pected from the use of pure zinc. reduces. the dissolving capacity of the alloy for Thus, it was attempted to roll into deep-drawiron that the alloy-can be melted in iron coning sheets the usual zinc die-casting alloys, with tainers without difiiculty. 0n the other hand, 0.2 their high elongation, but the attempt failed as per cent is the upper limit since alloys contain- 20 such alloys can be rolled into sheets only with ing more aluminium are not resistant to ageing. difiiculty or not at all, thesheets which could be The composition 01' our alloy may be varied, obtained possess. if any, only very limited deepas shown by the following examples: drawing capacity, and even this decreases with i ageing; r 2;

- Wehave made the surprising discovery that Perognwu Percent i; 25 these difilculties are overcome by determining 4 OJ the composition of the alloy as stated above, i. e., 5 0.1 Zinc practically free 4 to 5.5 per cent copper and 0.1 to 0.2 per cent g 8 from Mg and Cd. aluminium, and omitting the addition of magnesi- 51 5 0. 2 30 um made in the said die-casting alloys for suppressing intemystanme corrosion and cadmium Sheets rolled from such alloys have a tensile by using zinc practically free from these admix- Strength of 28 to 33 kilogrammes per square mum tures' meter, and an elongation of 60 to 40 per cent, as

Investlgauons have demonstrated that even against rolled 63 brass with a tensile strength of 35 an addition of magnesium of only 0.002 per cent 29 to 35 kilogrammes b Square millimeter and in a copper-aluminium-zinc alloy reduces its an elongation of about 45 per cent deep-drawing capacity to half and an addlmon Sheets from the new alloys according to our 3 22; 3%; xi'figsz mgg gfs it to A invention are preferably rolled crosswise, and 40 The influence of cadmium is also detrimental, ggg ggifi temperatures ranging from to grade. an addition of 0.002 per cent reducing the deep- The following table shows the result of a drawing capacity by about 10 per cent and an parative test between sheet rolled from the'alloy per cent reducing it by about 25 (2) of the table of compositions, and 0.4 milliper cen Y The 'following table shows the influence of meter thick and Sheet 3 f i fgfig magnesium and cadmium on the deep-drawing The test w made y e t Sen capaclty i in conformity with the Werkstofl-Handbuch for non-ferrous metals, sheet B".

oompositiop o1 Pnoy' per cent $32; I I Tensile Elonga- Erichsen 50 for sheet 0.4 Alloy strength, tion, per deep-drawing on .u Mg 0a Remainder millimeter kz/ cent values Millimctara 5 percent Cu, 0.2 percent Al, 40 Milli'irgeig g a 0.2 o. n 0.5 V

5 0.2 o. n 5.5 i g 3': {I The Erichsen value of alloy (2) is 18 to 19 mm.,

. 13 as against 12.2 mm; in 63 brass.

The following table shows the Erichsen values of various alloys as a function of their copper content.

Composition oi alloy, percent E im for sheet 0.4 Cu A] Zn mm. thick Millimeter;

that the Eriehsen value of electrolytic zinc having a purity of 99.99 per cent, and a tensile strength of 20 kg./qmm., is 117mm.

As mentioned, sheets from our alloys are preferably rolled crosswise, and at 180 to 220 centigrade. 'Temperatures above and below this range are detrimental to the deep-drawing ca-, pacity or the sheet.

We claim:

1. An alloy containing from 4 to 5.5 per cent of copper, from a small but eflective amount up to 0.2 per cent of aluminium, the remainder being zinc practically free from magnesium and cadmium.

. 2. An alloy containing Iroin 4 to 5.5 per cent of copper, 0.1 to 0.2 per cent or aluminium, the remainder being zinc practically tree from magnesium and cadmium.

KURT BAYER.

ARTHUR BURKHARDT. 20 

